use BatchMode instead of PasswordAuthentication for ssh (#664)
use BatchMode instead of PasswordAuthentication for ssh (#664)

DC/OS bumped the coreOS version, and just using PasswordAuthentication
is now no longer enough to turn off interactive mode. BatchMode covers
all types of authentication.
dcos/dcos-cli,mesosphere/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,mesosphere/dcos-cli,mesosphere/dcos-cli,sis-tools/dcos-cli,sis-tools/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,sis-tools/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli